magnesium in tetrahydrofuran; toluene soln. of bornyl chloride in THF was added to suspn. of Mg in THF, refluxed for 12 h, separated from Mg via cannula, distilled while toluene was constantly added to replace THF, kept at 111°C for 12 h, Ph3SnCl was added; detected by 119Sn NMR;